While convenient as a std::array, it's also quite a large set of data as
well (32KB). It being an array also means data cannot be std::moved. Any
situation where the code is being set or relocated means that a full
copy of that 32KB data must be done.
If we use a std::vector we do need to allocate on the heap, however, it
does allow us to std::move the data we have within the std::vector into
another std::vector instance, eliminating the need to always copy the
program data (as std::move in this case would just transfer the pointers
and bare necessities over to the new vector instance).
Namespaces all OpenGL code under the OpenGL namespace.
Prevents polluting the global namespace and allows clear distinction
between other renderers' code in the future.
This is an OpenGL renderer-specific data type. Given that, this type
shouldn't be used within the base interface for the rasterizer. Instead,
we can pass this information to the rasterizer via reference.
Before each draw call, for every enabled vertex array configured as instanced, we take the current instance id and divide it by its configured divisor, then we multiply that by the corresponding stride and increment the start address by the resulting amount. This way we can simulate the vertex array being incremented once per instance without actually using OpenGL's instancing functions.
We keep track of the current instance and update an uniform in the shaders to let them know which instance they are.
Instanced vertex arrays are not yet implemented.
Previously this would warn of truncating a std::size_t to a u32. This is
safe because we'll obviously never have more than UINT32_MAX amount of
uniform buffers.
Makes the global a member of the RendererBase class. We also change this
to be a reference. Passing any form of null pointer to these functions
is incorrect entirely, especially given the code itself assumes that the
pointer would always be in a valid state.
This also makes it easier to follow the lifecycle of instances being
used, as we explicitly interact the renderer with the rasterizer, rather
than it just operating on a global pointer.
This would result in a lot of allocations and related object
construction, just to toss it all away immediately after the call.
These are definitely not intentional, and it was intended that all of
these should have been accessing the static function GetInstance()
through the name itself, not constructed instances.
The GPU ignores that register when clearing, but OpenGL obeys the glDepthMask parameter, so we set the depth mask to GL_TRUE when clearing the depth buffer. It will be restored to the correct value automatically on the next draw call.
